ORL
Leuven, Vlaams-Brabant, 3000, Belgium
NCT Number: NCT02461797
Recently, a critical role in the development of allergic rhinitis (AR) has been attributed to the nasal epithelium. The airway epithelium forms a physical barrier, protecting the nasal mucosa and underlying organs from damage from contact with exogenous particles. The nasal epithelial barrier is primarily determined by the integrity of the airway epithelium, in which epithelial cells are connected to each other by complex network structures like tight junctions (TJs), ultimately sealing off the paracellular space. TJs consist of different transmembrane proteins including occludin, tricellulin, the claudin family, and junctional adhesion molecules. TJ form intercellular homodimers/heterodimers between neighboring cells. Scaffold adaptor proteins like cingulin and the zonula occludens family connect the transmembrane proteins to the actin cytoskeleton.
Disturbed TJ function can facilitate the entrance of foreign pathogens and antigens into the submucosal layer, giving raise to allergic sensitization via increased access of allergens to the dendritic cells and/or inducing persistent inflammation via activation of mast cells and other inflammatory cells residing in the upper airways. Chronic disorders like allergic asthma, inflammatory bowel disease and atopic dermatitis have been linked to defective or altered TJ function. Recently, an impaired epithelial barrier function was found in patients with chronic rhinosinusitis with nasal polyps (CRSwNP), suggesting changes in TJ arrangement in the nasal cavity. CRSwNP presents a similar inflammation of the sinonasal cavities as found in AR patients, i.e. a Th2 cytokine driven inflammation with tissue eosinophilia. Nevertheless, the role of TJs and its regulation has not been investigated in AR.
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Notify Me18 year–60 year
All sexes
Interventional
Not applicable
Leuven, Vlaams-Brabant, 3000, Belgium
Healthy volunteers accepted: Yes
Only the study team can determine whether someone qualifies for participation.
Inclusion criteria
Exclusion criteria
B. For AR group with use of nasal corticosteroid spray: Patients using other nasal or oral medication affecting nasal function, like anticholinergics, cromoglycates, leukotriene antagonists, ACE inhibitors less than 4 weeks before start of the study.
Healthy controls will meet the same exclusion criteria, with additional inclusion criteria:
biopsy of nasal mucosa for healthy controls
biopsy of nasal mucosa for allergic rhinitis patients without allergy medication
biopsy of nasal mucosa for allergic rhinitis patients with use of nasal corticoid spray
Time frame: every 30 min over 2 hours
Nasal biopsies will be mounted in modified 3 ml Ussing chambers. Experiments will be performed in open-circuit conditions. Transepithelial electrical resistance (TEER) will be calculated from the voltage deflections induced by bipolar constant-current pulses of 16 mA every 60 s with duration of 200 ms and will be recorded every 30 min over 2 h. The average of all time points of the 2 biopsy samples/patient will be used and will be presented as Ωxcm².
Time frame: every 30 min over 2 h
The paracellular probe, fluorescently labelled dextran 4 kDa (FD4) (2 mg/ml) will be used to determine the mucosal permeability. FD4 will be added to the mucosal compartment and serosal samples will be collected every 30 min over 2 h. The fluorescence level will be measured using a fluorescence reader. The average of time points 60, 90 and 120 min of the 2 biopsy samples/patient will be used to express mucosal permeability.
Universitaire Ziekenhuizen KU Leuven
Other
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